Know Sure Thing (KST) explained: how this multi-period momentum oscillator is calculated, interpreted, compared, and used with appropriate risk controls.
The Know Sure Thing (KST) is a momentum oscillator that combines four smoothed rate-of-change series covering different lookback periods. Despite its name, KST does not make an outcome certain. It summarizes short- through longer-term price momentum in one line and is normally plotted with a moving-average signal line.
For a lookback of n periods, rate of change is:
Each rate-of-change series is then smoothed. A general KST representation is:
where S is the selected smoothing method and w1 through w4 are weights. Many charting platforms use four progressively longer lookbacks and greater weights for the longer components, then plot a moving average of KST as the signal line. Exact defaults can differ, so the platform formula matters.
KST has no fixed upper or lower bound. Its magnitude depends on the asset’s price behavior and the settings used.
| Observation | What it describes | What it does not prove |
|---|---|---|
| KST above zero | The weighted momentum components are net positive | Price must continue rising |
| KST below zero | The weighted momentum components are net negative | Price must continue falling |
| KST crosses above its signal line | Measured momentum improved relative to its recent average | A profitable entry exists |
| KST crosses below its signal line | Measured momentum weakened relative to its recent average | A profitable short sale exists |
| Price and KST diverge | Price and the oscillator are not confirming each other | A reversal is immediate |
The direction and persistence of the indicator usually matter more than one isolated reading. A crossover that occurs repeatedly around the zero line may reflect a range-bound market rather than a durable trend.
Assume a stock remains in an uptrend. Its KST rises above zero and later crosses above its signal line. A trader might treat the crossover as confirmation that price momentum has improved, but not as a complete trade plan.
Before acting, the trader would still define the setup’s price level, invalidation point, position size, order type, and maximum acceptable loss. If KST crosses back below its signal line the next day, transaction costs and slippage could turn a seemingly useful signal into a loss.
| Indicator | Main construction | Typical output |
|---|---|---|
| Momentum | Current price versus one prior price | Unbounded change or percentage rate of change |
| KST | Four smoothed and weighted rate-of-change series | Unbounded composite oscillator plus signal line |
| Relative Strength Index | Average gains versus average losses | Bounded oscillator from 0 to 100 |
| Relative Strength | Asset performance versus a benchmark | Comparative ratio or relative return |
KST’s multi-period construction can smooth some short-term noise, but that same smoothing also introduces delay.
The CFTC glossary defines momentum and technical analysis in market terms. The CFTC also cautions readers to scrutinize claims made for trading systems and advisory services. These sources do not endorse KST or any specific trading rule.
This article is educational and does not provide personalized investment or trading advice. No technical indicator guarantees a return or limits loss.